The invention relates to an automobile-mounted automatic powder extinguishing device, and belongs to the technical field of fire-fighting extinguishing devices. The invention relates to an automatic extinguishing system integrating fire detection with extinguishing. Rapid, accurate and effective detection for a fire source can be realized by pressure-charged fire detection pipe and container bottle group by virtue of the own pressure storage, the automatic extinguishing system has the advantages of being simple to design and calculate, simple and convenient to construct and install, rapid andeffective in extinguishing, purely mechanical in automatic control and start-up, and is an automatic extinguishing system which is low-carbon, environment-friendly, simple, low in cost, highly reliable and independent. According to the automobile-mounted automatic powder extinguishing device disclosed by the invention, container bottles are arranged outside an engine cabin, so that influence on the sealing performance of the container bottles when the temperature of the engine cabin part liable to cause fire, on an automobile, is high during the running of the automobile, is reduced; and moreover, the fire detection pipe is arranged in the form of S-shape, free from dead angles in fire prevention, capable of stretching into the engine cabin with a complex structure and really realizing nodead angles in safety protection, applicable to various occasions, and capable of realizing no blank in protection.